The move was viewed with consternation by many in the banking industry, and a formal statement of government policy was thought necessary, according to sources. “These banking laws have been on the books for years, but nobody has taken them very seriously,” said one banker who declined to be named because he was afraid of everything. “Now all of a sudden they’re coming after us with hammer and tongs. It’s just not fair.”

Federal authorities disagree. In recent weeks, they have demonstrated a flurry of activity, cracking the Madoff case (after Mr. Madoff confessed) and moving smartly in to arrest Robert Allen Stanford before his alleged fraud reached an even $10 billion. At the same time, investigation into thousands of e-mails sent by UBS to clients attempting to avoid onerous taxation is now underway. Some of these e-mail date back to 2004.

“We’ve been very busy enforcing a variety of accounting rules at essentially law-abiding corporations,” said a government official who declined to be named on general principle, “but now we’re going to take a hard look at some of the laws that may need more active enforcement. There are a lot of them, you know. And we’re very short-staffed.”

Analysts conjectured that the change of policy may have something to do with the new administration. “I don’t think the reduction of taxation by virtually any means necessary was viewed as a punishable offense until very recently,” said one, adding, “And now if you’ll excuse me, I’m headed to the Cayman Islands on a completely unrelated matter.”